Thread: bead and cove sets for strip planking

Do you need to bead and cove the strips if they are only 3.5mm thick?

In a recent couple of articles in Wooden Boat magazine a guy builds a stip planked canoe using thin strips and he just bevels the edge of each strip as he goes. Didn't look too hard since the strips were so thin.

http://www.leevalley.com/wood/page.a...currency=2&sid=

http://www.routerbits.com/cgi-router...429405_2347+62

http://allita.net/Projects/omnicat5/index.php?cat_id=0

Try these outfits, plus www.woodcraft.com

Thanks for the links.

Mikey- I'm still considering this as an option. The person I got the strips off built a rowing shell from the same strips and didn't bead/cove them, just bevelled.

Can take just as long to do it either way, and if I can't get appropriate router bits then I may bevel them. But as they're rolling bevels it can be hard to get a close fit, and any gaps are filled with epoxy which adds to the weight.

Regards,
Darren

Howdy TK1

3.5mm sounds a bit thin - are you sure the plans specify this thickness?

it is not uncommon to remove a millimetre or more during the fairing - this will be a very thin structure.

I would suggest double checking the plans unless you are really sure already.

If needing to build light it is often better to choose a light density timber and make it thicker as this gives you greater hull stiffness. And glass weighs so much compared to timber that it is a much better place to concentrate weight savings.

Lightweight canoe structure

But go with the designer of course!

But this is just a check to make sure you have the skin thickness right - at such small thicknesses there will not be much of a cusp or cove.

Michael

Hi Mick,

Yes, 3.5mm is thin. It's a little thinner, at 3/16", than the designers (Nick at Guillemot kayaks, and a David Payne design) intended, but they assuered me it would work - yes, as long as I'm careful with the sanding!

It will be for a racing and fast kayak, and possibly a canoe, projects, not intended to carry heavy loads or operate in extreme sea conditions - just flatwater. Certainly won't be making a Snapper Boat or anything out of them

A couple of other builders out here have used the same timber (a one-time source that was found of ready-milled 3.5mm western red cedar) and so far a sea kayak (again Guillemot design) and two rowing shells (single sculls) have been made from the same timber. The sculls especially are very light, with lightweight peel ply used on the outside only. And paddling in Botany bay at race speeds hasn't seen any damage to the hull.

As they are thin strips, I may end up just bevelling them. I wanted to put a bead and cove on a few strips and try it out anyway, to see which was the most effective method for the planks.


Regards,
Darren

What weight of glass are they recommending?

Have you considered using Paulownia - it will save you some weight and cost over cedar.

Michael

Hi Michael,

Glass will be 130 or 200 gsm - I'd prefer the lighter but want to do a strength test with a sample I have first, to ensure the glas-wood-glass structure is sound. Designers thinks so, but I plan to lay up a long strip and check longitudinaly strength, rigidity and impact resistance.

Although for the racing boat at least I'll be using carbon fibre on the bottom of the hull for impact resistance as some races are in rivers and we hit the occaisional submerged log.

I have just bought some paulowning for stringers in a ply raeing kayak I'm doing first. Lovel stuff, straight grained and light. I'm considering using it for a kayak too. However, I already have the WRC (50mm wide strips, about 400 linear meters of it!) at almost no cost (had to pick it up from Sydney) so it's there, free, and nice wood so I plan to use it

There will be plenty more boats in the future, and paulownia is on the list for at least one...

Regards,
Darren

On strips that thin, I wouldn't bother with all the machine work, putting in coves and beads. A couple of passes with a plane will quickly put a bevel on planks with those minimum thickness. No, they're not "self aligning" like the cove and beads are, but stock that light is easily manipulated with tape, brads, staples, tacks, etc.

I use a "U" shaped clip that fits over the upper most plank with it's legs reaching down to the one fastened below. This helps align the surly strips, while I fasten them (I use several per planks at times)

I sold 4.5 mm strips to a kayak builder who was building his craft with advice from Bob Macks Laughing Loon CC & K. I felt he was a Yank. Any way he advised that he preferred using 4.5 mm without D & C.

Maybe it worth visiting his web site to find out more.